Method of preparing meso-haloalkylporphyrins

ABSTRACT

Transition metal complexes of meso-haloalkylporphyrins, wherein the haloalkyl groups contain 2 to 8 carbon atoms have been found to be highly effective catalysts for oxidation of alkanes and for the decomposition of hydroperoxides. Also disclosed is a process for the preparation of meso-halocarbyl-porphyrins which comprises contacting a halocarbyl dipyrromethane with a halocarbyl-substituted aldehyde in the presence of an acid granular solid catalyst. Also disclosed is a process for the preparation of meso-halocarbyl-porphyrins which comprises contacting a halocarbyl dipyrromethane with a halocarbyl-substituted aldehyde in the presence of an acid granular solic catalyst.

The Government of the United States of America has rights in thisinvention pursuant to Cooperative Agreement No. DE-FC21-90MC26029awarded by the U.S. Department of Energy.

This is a divisional of application Ser. No. 08/405684 filed on Mar. 17,1995, now U.S. Pat. No. 5,608,054, which application is acontinuation-in-part of application Ser. No.08/174,732 filed Dec. 29,1993 now U.S. Pat. No. 5,571,908 and of application Ser. No. 08/175,057filed Dec. 29, 1993, now abandoned.

BACKGROUND

Electron deficient metalloporphyrins are efficient catalysts for thehighly selective air oxidation of light alkanes to alcohols, P. E. Ellisand J. E. Lyons, Cat.Lett., 3, 389, 1989; J. E. Lyons and P. E. Ellis,Catt.Lett., 8, 45, 1991; Lyons and Ellis, U.S. Pat. Nos. 4,900,871;4,970,348, as well as for efficient decomposition of alkylhydroperoxides, Lyons and Ellis, J. Catalysis, 141, 311, 1993; Lyons andEllis, U.S. Pat. No. 5,112,886. They may be prepared by theco-condensation of pyrrole with the appropriate aldehyde, Badger, Jonesand Leslett, Aust.J.Chem., 17, 1029, 1964; Lindsey and Wagner,J.Org.Chem., 54, 828, 1989; U.S. Pat. Nos. 4,970,348 and 5,120,882,followed by metal insertion, Adler, Longo, Kampos and Kim,J.Inorg.Nucl.Chem., 32, 2443, 1970, and β-halogenation, U.S. Pat. Nos.4,892,941 and 4,970,348. Other patents disclosing use of metalcoordination complex catalysts in oxidation of alkanes are Ellis et alU.S. Pat. Nos. 4,895,680 and 4,895,682.

Meso-tetrakis(perhaloalkyl)porphyrins, for examplemeso-tetra(trifluoromethyl)porphyrin, have been prepared by theself-condensation of the corresponding 2-hydroxy(perhalo-alkyl)pyrroleby prior activation of the hydroxy leaving group, Wijesekera, U.S. Pat.No. 5,241,062.

t-Butyl alcohol has been prepared by the catalytic decomposition oft-butyl hydroperoxide (TBHP), preferably in solution in t-butyl alcohol,in the presence of a metal phthalocyanine of a metal of Group IB, GroupVIIB or Group VIIIB, for example chloroferric phthalocyanine and rheniumheptoxide-p-dioxane or oxotrichloro-bis(triphenylphosphine) rhenium,Sanderson et al U.S. Pat. No. 4,910,349.

t-Butylhydroperoxide may be decomposed to t-butyl alcohol using a metalporphine catalyst, for example tetraphenylporphine, optionally promotedwith a thiol and a heterocyclic amine, Sanderson et al, U.S. Pat. No.4,922,034, or using an imidazole-promoted phthalocyanine (PCY) catalyst,for example Fe(III)PCYCl or Mn(II)PCY or VOPCY, Sanderson et al U.S.Pat. No. 4,912,266.

Isobutane may be converted continuously to isobutyl alcohol by a processincluding the step of deomposing t-butylhydroperoxide to t-butylalcohol, using a monocyclic solvent and a PCY decomposition catalyst,Marquis et al U.S. Pat. No. 4,992,602.

t-Butylhydroperoxide may be decomposed to t-butyl alcohol using a metalporphine catalyst such as a trivalent Mn or Fe tetraphenylporphine,optionally promoted with an amine or thiol, or a soluble Ru catalystpromoted with a bidentate ligand such as Ru(AcAc)₃ promoted withbis(salicylidene)ethylenediamine, or a promoted PCY catalyst such as aMn, Fe or vanadyl PCY promoted with an amine, a Re compound such as NH₄ReO₄, a mercaptan and a free radical inhibitor, a base or a metalborate, Derwent Abstract (Week 8912, Other Aliphatics, page 58) ofreference 89-087492/12 (EP 308-101-A).

Hydroperoxides may be decomposed with metal ligand complexes in whichhydrogen in the ligand molecule has been substituted withelectron-withdrawing elements or groups, for example halogen or nitro orcyano group, Lyons et al U.S. Pat. No. 5,120,886, which is incorporatedby reference herein,

OTHER PUBLICATIONS

S. G. DiMagno. R. A. Williams and M. J. Therien, "Facile Synthesis ofmeso-Tetrakis(perfluoroalkyl)porphyrins: Spectroscopic Properties andX-ray Crystal Structure of Highly Electron-Deficient5,10,15,20-Tetrakis-(heptafluoropropyl)porphyrin.", J.Org.Chem. Vol. 59,No. 23, pp 6943-6948 1994.

M. J. Therien et al U.S. Pat. No. 5,371,199 issued Dec. 6, 1994 from anapplication filed Aug. 14, 1992, discloses meso-haloalkylporphyrinshaving 1 to 20 carbon atoms in at least one haloalkyl group,beta-haloalkylporphyrins having 2 to 20 carbon atoms in at least onehaloalkyl group, beta-haloalkylporphyrins having 1 to 20 carbon atoms inat least five haloalkyl groups, and beta-haloarylporphyrins having 6 to20 carbon atoms in at least five haloaryl groups.

Linear porphyrin arrays synthesized via reactions including CF₃CHO+pyrrole to afford trifluoro dipyrromethane are disclosed in theabstract of a poster at the American Chemical Society Division ofOrganic Chemistry meeting in San Diego, Calif. Mar. 13-17, 1994 by R. W.Wagner, N. Nishino and J. S. Lindsey, "Building Block Synthesis ofLinear-Amphipathic Porphyrin Arrays".

DESCRIPTION OF THE INVENTION

The invention comprises new compositions of matter having the structuralformula: ##STR1## where M comprises a transition metal such as iron,manganese, cobalt, copper, ruthenium, chromium and the like, R³ and R⁶comprise at least one haloalkyl group containing 2 to 8 carbon atoms,and R¹, R², R⁴ and R⁵ are independently hydrogen, hydrocarbyl, orelectron-withdrawing substituents, for example halogen, nitro, cyano orhalocarbyl. Anions such as azide, halide, hydroxide or nitride may beassociated with the metal M. Porphyrins having the formula I includeporphyrins comprising two or more meso-halocarbylporphyrins in dimericor mu-oxo dimer forms or polymeric forms as known in the porphyrin art.

The compounds according to the invention are haloalkylporphyrins andmetal complexes thereof containing in a meso position or positions atleast one straight or branched chain haloalkyl group having 2 to 8carbon atoms, and more preferably 3 to 6 carbon atoms, in the haloalkylgroup. Preferred haloalkyl groups in the porphyrins according to theinvention are straight or branched chain heptafluoropropyl groups.

The porphyrins according to the invention may contain differenthalocarbyl groups in different meso positions, as in the compound, Fe(C₆F₅)₂ (C₃ F₇)₂ P!₂ O, where P is porphyrin, R⁶ in formula I is C₆ F₅ andR³ in formula I is C₃ F₇, or may contain the same halocarbyl group ineach of the substituted meso positions, as in the compound Fe(C₃ F₇)₄P!₂ O, where P in Formula I is porphyrin, and R³ and R⁶ are eachheptafluoropropyl.

CATALYST PREPARATION

The compounds according to the invention may be prepared for example byreaction of a halopropyl-substituted dipyrromethane such asbis(pyrrol-2-yl)heptafluoropropylmethane (FIG. 7, 1) with ameso-halopropyl-substituted aldehyde (FIG. 7, 2, R=CF₂ CF₂ CF₃) in thepresence of a catalyst such as a solution of hydrobromic acid in aceticacid to obtain an intermediate porphyrinogen, followed by treatment ofthe intermediate porphyrinogen with1,2-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) to producemeso-tetrakis(heptafluoropropyl)porphyrin (FIG. 7, 3b. The iron complexof meso-tetrakis(heptafluoropropyl)porphyrin is typically prepared byreaction of the meso-tetrakis(heptafluoropropyl)porphyrin with ferrouschloride in acetic acid and sodium acetate.

An acidic granular solid catalyst such as montmorillonite clay may beused as catalyst, instead of HBr-CH₃ COOH, for the reaction of adipyrromethane with an aldehyde to produce an intermediateporphyrinogen, with substantially improved results, for example twicethe yield, over those obtained with HBr-CH₃ COOH. Other known acidicgranular solid catalysts may also be used, such as other acidic clays,acidic zeolites, solid superacids such as sulfated zirconia, and thelike. Other known methods for preparing meso-halocarbylporphyrins may beadapted for the preparation of the meso-halocarbylporphyrins accordingto the invention, by a person skilled in the art in the light of thepresent specification.

OXIDATION PROCESSES

Transition metal complexes of the compositions according to theinvention are highly effective catalysts for the oxidation of organiccompounds. Generally, such catalysts are useful in those oxidations oforganic compounds for which transition metal complexes of porphyrins,and particularly halogen-containing porphyrin structures are useful, asknown in the art. See for example Lyons and Ellis U.S. Pat. Nos.4,900,871 and 4,970,348 supra.

The oxidation, which may be carried out in a generally known manner, isdesirably conducted in the liquid phase, although this is not critical,using such organic solvents as benzene, acetic acid, acetonitrile,methyl acetate, or like solvents which are inert to the conditions ofthe reactions, or in a neat solution of the hydrocarbon if it is liquid,and under pressures ranging from about 15 to 1500 psig, preferably 30 to750 psig, at temperature of from about 25° to 250° C., preferably 70° to180° C. Depending upon whether the hydrocarbon to be oxidized is asolid, liquid or gas, it is dissolved in or bubbled through the solvent,together with air or oxygen, in the presence of catalyst for periods oftime sufficient to yield the desired oxidation product, generally fromabout 0.5 to 100 hours, and preferably from 1 to 10 hours.

The choice of solvent, while not critical, can have an effect on therates and selectivities obtained and should be selected carefully inorder to optimize the desired results. For example, solvents such asacetonitrile and acetic acid are often very effective for the oxidationof alkanes to form oxygen-containing compounds, whereas reactionscarried out in solvents such as methyl acetate or benzene occur moreslowly.

The ratios of the various reactants may vary widely, and are notcritical. For example, the amount of catalyst employed can range fromabout 10⁻⁶ to 10⁻³ mole of catalyst per mole of hydrocarbon such asalkane, and more preferably from about 10⁻⁵ to 10⁻⁴ mole of catalyst permole of hydrocarbon, although other amounts are not precluded; while theamount of oxygen relative to the hydrocarbon starting material may alsovary widely, generally 10⁻² to 10² moles of oxygen per mole ofhydrocarbon. Care should be taken since some of the ratios fall withinexplosive limits. As a group, the catalysts are almost always solubleunless used in high concentration. Thus, as a rule, the reactions arecarried out homogeneously.

OXIDATION SUBSTRATE

The substrate for the process for oxidation of organic compounds, usingthe composition of the invention as catalyst may be an alkane such asmethane, ethane, propane, n-butane, isobutane, n-pentane, isopentane,and the like, or an alkyl-substituted cyclic compound such as toluene,xylene, mesitylene and the like. Preferably but not necessarily, thesubstrate contains 1 to 10 carbon atoms in the molecule. Mixtures ofcompounds can be used.

HYDROPEROXIDE DECOMPOSITION PROCESSES

Transition metal complexes of the compositions according to theinvention are highly effective catalysts for the decomposition oforganic hydroperoxides. Generally, such catalysts are useful in thosedecompositions of organic hydroperoxides for which transition metalcomplexes of porphyrins, and particularly halogen-containing porphyrinstructures are useful catalysts, as known in the art. See for exampleLyons and Ellis U.S. Pat. No. 5,112,886 supra.

The hydroperoxide decomposition process according to the invention maybe carried out in any known manner for decomposing hydroperoxides, usinghowever the catalyst of the invention instead of the known catalysts ofthe prior art. The decomposition is preferably performed with thehydroperoxide dissolved in a suitable organic solvent, which may forexample be the alcohol which is formed by the decomposition of thehydroperoxide. Any suitable temperature and pressure may be used, asknown in the art for hydroperoxide decomposition processes. A preferredtemperature is in the range from 25° to 125° C. Because of the rapidreaction rate of the catalysts used according to the invention, thereaction times may be fairly short, in the range from 0.1 to 5 hours,preferably 0.1 to 1 hour.

HYDROPEROXIDE DECOMPOSITION SUBSTRATE

Hydroperoxides which may be decomposed according to the inventioninclude compounds having the formula ROOH, where R is an organicradical, typically a straight or branched chain alkyl or cycloalkylgroup containing 2 to 15 carbon atoms, an aryl group such as amonocyclic or polycyclic group in which the cyclic groups may optionallybe substituted with one or more substituents inert to the decompositionreaction, such as alkyl or alkoxy, containing 1 to 7 carbon atoms,nitro, carboxyl or carboxyl ester containing up to about 15 carbon atomsand a halogen atom such as chloride, bromide, or an alkaryl group inwhich the alkyl chain contains from 1 to 15 carbon atoms and the arylgroup is as above described. Preferably R is an alkyl or cycloalkylgroup containing 4 to 12 carbon atoms or an alkaryl group in which thearomatic moiety is phenyl and the alkyl substituent is straight orbranched chain alkyl or cycloalkyl containing up to about 6 carbonatoms. Examples are t-butyl and isobutyl hydroperoxide, isoamylhydroperoxide, 2-methylbutyl-2-hydroperoxide, cyclohexyl hydroperoxide,cyclohexylphenyl hydroperoxide, phenethyl hydroperoxide and cumylhydroperoxide, the latter two of which are converted to phenethylalcohol and cumyl alcohol, respectively.

DRAWINGS

FIG. 1 shows the mole % of reactant, isobutane (IC4), and product,tertiary butyl alcohol (TBA), as a function of time in the oxidation ofisobutane at 80° C. and 35 psia O₂, using 32 mg of Fe PPF₂₈ H₈ !X, whereX is a halogen. FIG. 2 shows ln(C, mole %) of isobutane as a function oftime in the same oxidation run.

FIG. 3 shows mole % of reactant and product as a function of time in theoxidation of isobutane in a second run at the same conditions and withthe same catalyst as in the run of FIGS. 1 and 2. FIG. 4 shows ln(C,mole %) of isobutane as a function of time in the second run.

FIGS. 5 and 6 show the mole % of reactant and product and ln(C, mole %)of isobutane in a third run at 80° C. and 35 psia O₂, using 40 mg of thesame catalyst as in the first and second runs.

FIG. 7 is a graphic depiction of reaction paths for production of atypical compound according to the invention.

EXAMPLES Example 1 Preparation of 5,15-bis(heptafluoropropyl)-10,20-bis(pentafluorophenyl)porphyrin

Equimolar quantities of bis(pyrrol-2-yl)heptafluoropropylmethane 1 andpentafluorobenzaldehyde (FIG. 7, 2a; R=C₆ F₅) were heated at reflux for10-20 h in degassed chloroform containing montmorillonite K10 clay ascatalyst. The reaction mixture was treated with a solution of2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in benzene and refluxcontinued for a further 20 h. The clay catalyst was removed byfiltration and the desired porphyrin,5,15-bis(heptafluoropropyl)-10,20-bis(pentafluorophenyl)porphyrin 3a;R=C₆ F₅); Fe(C₆ F₅)₂ (C₃ F₇)₂ PH₂ ; P=porphyrin! isolated by passingthrough neutral alumina and crystallization from dichloromethane/methanol. MS(FAB): m/z=979 (M+1); UV: λ_(max), 388 (Soret), 428 (sh),560, 598 nm.

Example 2 Preparation of 5,10,15,20-tetrakis(heptafluoropropyl)porphyrin

The porphyrin 5,10,15,20-tetrakis(heptafluoropropyl)porphyrin FIG. 7,3b; R=C₃ F₇ ; (C₃ F₇)PH₂ ! was prepared as described in Example 1 usingheptafluorobutyraldehyde (FIG. 7, 2b; as the hydrate) instead ofpentafluorobenzaldehyde (FIG. 7, 2a). MS(FAB): m/z=984 (M+2); UV:λ_(max), 404 (Soret), 508, 544, 590, 646 nm.

Example 3 Preparation of 5,15-bis(heptafluoropropyl)-10,20-bis(pentafluorophenyl)porphyrinatoiron

The porphyrin FIG. 7, 3a prepared in Example 1 (400 mg) and sodiumacetate (500 mg) were heated to near reflux in degassed acetic acid (200mL) and treated with ferrous chloride (500 mg). The heating wascontinued for 30 min under argon and the solution was allowed to stirovernight at room temperature exposed to air. Hydrochloric acid (3M, 200mL) was added, the solid filtered, washed with 1M hydrochloric acid anddried in a desiccator. The crude iron complex was redissolved inchloroform, extracted with 2M aqueous sodium hydroxide and passedthrough neutral alumina (15% water added), eluting with chloroform. Thepure iron complex FIG. 7, 4a (R=C₆ F₅) was isolated by evaporating thesolvent. MS(FAB): 1032 (M-X); UV: λ_(max), 388 (Soret), 428 (sh), 560,598 nm.

Example 4 Preparation of5,10,15,20-tetrakis(heptafluoropropyl)porphyrinatoiron

The crude iron complex FIG. 7, 4b was prepared as described in Example 3using the porphyrin FIG. 7, 3b prepared in Example 2. Purification wascarried out by passing a chloroform solution through neutral alumina(15% water added) and the pure product isolated by evaporation of thesolvent. MS(FAB): 1036 (M-X); UV: λ_(max), 396 (Soret), 566, 600 nm.

Examples 5-11 Oxidation of isobutane usingmeso-perfluoropropylporphyrinatoiron catalysts

Isobutane was oxidized to tertiary butyl alcohol usingmeso-perfluoropropylporphyrinatoiron catalyst and conditions as setforth in footnote a to Table 1. Table 1 shows the results.

                  TABLE 1                                                         ______________________________________                                        Oxidation of Isobutane Using meso-Perfluoro-                                  propyl Porphyrinato Iron Catalysts                                            Complex      T, °C.                                                                          t, hrs  TO.sup.b                                                                            TBA Sel, %.sup.c                          ______________________________________                                        Fe(OEP)Cl    60      6        0     --                                        Fe(TPP)Cl    60      6        0     --                                        Fe C.sub.6 F.sub.5).sub.4 P!Cl                                                             60      6        1100  90                                         Fe(C.sub.6 F.sub.5).sub.2 (C.sub.3 F.sub.7).sub.2 P!.sub.2 O                              60       6.sup.d 90    NA                                                             12       710   90                                         Fe(C.sub.3 F.sub.7).sub.4 P!.sub.2 O                                                      60       6.sup.e 110   NA                                                             12       1110  81                                        ______________________________________                                         .sup.a The catalyst, 0.013 mmole, was dissolved in 25 ml benzene to which     7.0 g iC.sub.4 H.sub.10 was added. Oxygen (to 100 psig) was added at          reaction temperature and the mixture stirred for the designated time.         Product analysis by glpc, gas liquid phase chromatography.                    .sup.b Moles O.sub.2 taken up/mole catalyst after reaction time               .sup.c (moles tertiary butyl alcohol formed/moles iC.sub.4 H.sub.10           reacted) × 100                                                          .sup.d Reaction had a 5 hour induction period.                                .sup.e Reaction had a 3 hour induction period                            

Examples 12-14

                  TABLE 2                                                         ______________________________________                                        Decomposition of tert-butyl Hydroperoxide Catalyzed By                        meso-Perfluorocarbyl Porphyrinato Iron Complexes.sup.a                                  O.sub.2 Evolution.sup.b in time t, hr                               Complex.sup.d                                                                        T, °C.                                                                          1      2     3    4     RO.sub.2 H Conv..sup.c                ______________________________________                                        A      80       1300   NA    NA   1375  92.5%                                 B      80       1000   NA    1300 1390  94%                                   C      80       1130   1260  1325 1400  >95%                                  D      80        365    445   450  450  31%                                   ______________________________________                                         .sup.a The catalyst, 0.60 mg, was added directly to a stirred solution of     tertbutyl hydroperoxide, 13.8 g, (dried thoroughly over activated 3A mole     sieves prior to use) in tertbutyl alcohol, 18.1 g, at 80° C. Oxyge     evolution was measured manometrically. Liquid products were analyzed by       glpc before and after the runs.                                               .sup.b Oxygen evolved in cc's.                                                .sup.c  (moles RO.sub.2 H.sub.init - moles RO.sub.2 H.sub.final)/moles        RO.sub.2 H.sub.init ! × 100                                             .sup.d A = Fe C.sub.6 F.sub.5).sub.4 P!Cl                                     B =  Fe(C.sub.6 F.sub.5).sub.2 (C.sub.3 F.sub.7).sub.2 P!.sub.2 O             C =  Fe(C.sub.3 F.sub.7).sub.4 P!.sub.2 O                                     D =  Fe(CF.sub.3)P!.sub.2 O                                              

The invention claimed is:
 1. Process for the preparation ofmeso-halocarbylporphyrins which comprises contacting a halocarbyldipyrromethane with a halocarbyl-substituted aldehyde in the presence ofan acidic granular solid catalyst.
 2. Process according to claim 1 whichwherein said halocarbylporphyrin is ameso-tetrakis(perhaloalkyl)porphyrin, said halocarbyl dipyrromethane isa bis(pyrrol-2-yl)perhaloalkane, and said aldehyde is aperhaloalkyl-substituted aldehyde.
 3. Process according to claim 2wherein said halocarbyl dipyrromethane isbis(pyrrol-2-yl)trifluoromethylmethane, and said aldehyde istrifluoroacetaldehyde methyl hemiacetal.
 4. Process according to claim 2wherein said halocarbyl dipyrromethane isbis(pyrrol-2-yl)heptafluoropropylmethane, and said aldehyde isheptafluorobutyraldehyde.
 5. Process according to claim 3 wherein saidcatalyst is montmorillonite.